Heavy duty trucks--especially those trucks weighing more than 3.6 metric tons (8,000 pounds), generally have air brakes. Air brakes, as do all brakes, need adjustments. In order to accomplish this adjustment, an adjusting nut has been placed on a slack adjuster in a common fashion for adjusting air-brakes. Unfortunately this adjusting nut is exposed to the elements and heavy duty wear that a truck of this type normally endures. With the exposure to the elements, the slack adjusting nut becomes corroded and difficult to operate. With such corrosion, the adjusting of the slack on the air-brakes becomes difficult if not impossible.
Slack adjusters are found on all air-brake trucks. This includes trucks weighing more than four tons; such as tractor trailers. It is highly desirable to protect the adjusting nut from the elements. Yet there is no current device capable of providing reliable protection for the adjusting nut.
A truck driver is known to use rags or other implements to protect the adjusting nut from the elements. The rags do not absorb the pounding and exposure to the elements common to such heavy duty trucks. The countervailing factor coming with the protection of the adjusting nut is that accessibility to the adjusting must also be maintained. Such protection is of little value if accessibility is not maintained.
A truck driver has a tendency, especially in inclement weather, to postpone slack adjustments to brakes. The adjustments are difficult and irritating due to dirt, moisture, and grime which clog the adjusting nut on the slack adjuster.
The corrosion can lead to the breaking of the adjusting nut on the slack adjuster, when an attempt to move the nut is attempted. If the adjusting nut breaks, the entire slack adjuster must be replaced. Since there are about eight slack adjusters on each vehicle, replacement of these parts on a truck can be expensive. It is desirable to find a method and device of protecting the adjusting nut so that the slack adjusters can last, and not have the adjusting nut break or fail to act, when an adjustment is required.
In an attempt to overcome the problem with the manual slack adjusters, automatic slack adjusters are known. However, these adjusters are not sufficient and not durable. In fact, the automatic slack adjusters are not usually left on the vehicle by most drivers, because they do not work well enough to please the driver. Additionally, a truck driver feels more comfortable with a personally adjusted adjusting nut.